New conditions attached by Clive Palmer to the activation of his proposed “dormant” emissions trading scheme (ETS) mean it is unlikely to ever happen and will now be opposed by Labor, even though it supports emissions trading.

The dormant scheme was a key part of Palmer’s surprise announcement alongside the former US vice-president Al Gore and at the time he said it would be activated “based upon the actions of our leading trading partners China, the United States of America, the European Union, Japan and Korea”.

The “trigger” for activating the ETS has varied during the drafting of the plan, which will be presented as an amendment to legislation abolishing the Climate Change Authority.

At times during negotiations the amendment has been worded flexibly, requiring trading partners to reduce emissions by an equivalent amount to Australia’s efforts, whether through a nationwide ETS or “equivalent” policies.

But now the Palmer United party (PUP) is insisting trading partners meet their emissions reduction promises with an emissions trading scheme, and has added India to the list at the last minute.

The deputy chief executive of the Climate Institute, Erwin Jackson, said the new conditions contradicted PUP's claim to be in favour of global action on climate change.

"Given India’s historic role internationally in pushing for equitable contributions from countries, it would be a toxic bomb to international negotiations now if Australia indicates that credible action is conditional on similar action from countries like India," Jackson said. "It would certainly work against the PUP push for more global action."

The changes mean the “trigger” is unlikely to be met for many years, because even if other countries adopt ambitious greenhouse targets they may not choose to implement them with a nationwide ETS. The EU and Korea have a carbon price. The US has a price in only some states after Barack Obama failed to get his cap-and-trade scheme through Congress. Obama is now moving to meet emissions reduction targets through strict regulations, including on power station emissions. China has some regional emissions trading schemes but no national scheme. India has a small tax on coal, but as a developing country is unlikely to take on similar policies to Australia and its other trading partners.

"No 1, there's an ETS in the following basket of countries which include India, China, South Korea, Japan, the United States and the [EU] – they've got to have a national ETS for ours to be effective," Palmer said when asked about the plan on Monday.

"Secondly, the price of carbon has got to be such that it doesn't affect our business competitiveness with those countries.

"And the third thing, it can be disallowed by the houses of parliament."

Sources said the last-minute changes mean Labor, which had been considering the amendment, cannot support it and the fate of the amendment is unclear. The government has also reiterated that it does not support emissions trading.

The Climate Change Authority repeal bill, to which the amendment would be attached, is on the list of bills the government is demanding a vote on before the Senate breaks for its winter recess, but that list is under negotiation between the parties. The climate change authority repeal bill may be delayed until August.

Palmer’s stance on the issue of global warming has been varied. This week he said: “When it comes to fighting climate sceptics you have to persevere.”

But before the election, when asked by the ABC whether he agreed global warming would have a big impact on Australia, he said: “No, I don't believe that's so. There's been global warming for a long time. I mean, all of Ireland was covered by ice at one time. There were no human inhabitants in Ireland. That's how the world has been going over millions and billions of years and Ross Garnaut knows that's true, so I think that's part of the natural cycle.”